In this paper we focus on a visualization tool for car crash simulations. By means of some examples we show how various data pre-processing features can facilitate the engineer's work. For example, parts can be assembled, replaced, welded, bonded, or deformed. Data pre-processing within the visualization tool means that some modifications can be done directly on the finite element mesh which is the input for the crash simulation. Some of the features are new within a crash visualization environment and some operations needed new algorithms to be developed: We present the generation of curved spotweld lines and adhesive bondings along flanges. Further we show how modern hardware features like textures and alpha blending can be employed for efficient visualization in the context of data pre-processing. The new features allow crash simulations in an early development phase, they also allow to test the impact of a potential improvement or to remove some shortcomings due to mesh gener...